SLEEP. 



689 



this point, and directed at pleasure the cha- 

 racter of his dreams. In his first experiment, 

 having allowed the back of his head to be 

 uncovered during sleep, he thought he was at 

 a religious ceremony in the open air ; the 

 custom of the country in which he lived being 

 to keep the head covered excepting on some 

 rare occurrences, among which was the per- 

 formance of religious ceremonies. On waking 

 he felt cold at 'the back of the neck, as he 

 frequently had when present at the real cere- 

 monies. He repeated the experiment in two 

 days, with the same result. In a third ex- 

 periment, he left his knees uncovered, and 

 dreamt that he was travelling at night in the 

 diligence; and all travellers know, he observes, 

 that it is chiefly at the knees that they feel 

 cold when travelling by that conveyance at 

 night. The very remarkable degree in which 

 this influence of external impressions is ex- 

 erted, when sleep is being induced by the 

 agency of certain narcotics, will be presently 

 noticed. By the use of the term " external " 

 is here meant that which is external to the 

 mind itself. The dream may originate in im- 

 pressions derived from any part of the bodily 

 frame. Thus we find that indigestion is a 

 very common cause of nightmare, and that 

 an irritable state of the genital apparatus 

 provokes lascivious dreams. When the ex- 

 ternal impressions are recognized as sensa- 

 tions, and the dreamer's current of thought 

 completely follows their guidance, so that 

 even the meaning of spoken language is ap- 

 preciated, the condition approximates to that 

 of Somnambulism. 



One of the most remarkable of all the pecu- 

 liarities of the state of dreaming, is the rapidity 

 with which trains of thought pass through 

 the mind ; a dream in which a long series of 

 events has seemed to occur, and a multitude 

 of images has been successively raised up, 

 being often certainly known to have occupied 

 but a few minutes or even seconds. This is 

 best seen in those cases in which the dream has 

 obviously originated in some sensory impres- 

 sion, which has also had the effect of arousing 

 the sleeper. A very interesting example of 

 this, in which a similar dream was produced 

 in two individuals, husband and wife, from 

 the same cause, came within the knowledge 

 of the late Dr. James Gregory. It happened 

 when the public mind was much excited in 

 regard to the alarm of French invasion, and 

 the gentleman who was the subject of it was 

 himself a zealous member of the Edinburgh 

 volunteer corps. Whilst asleep, between two 

 and three o'clock in the morning, he dreamt 

 of hearing the signal gun: he was immediately 

 at the Castle, witnessed the proceedings for 

 displaying the signals to alarm the country, 

 and saw and heard a great bustle over the 

 town, from troops and artillery assembling, 

 especially in Princes Street. At this time 

 he was roused by his wife, who awoke in a 

 fright, in consequence of a similar dream, 

 connected with much noise and the landing of 

 the enemy, and concluding with the death of 

 a particular friend of her husband's, who had 



VOL. IV. 



served with him as a volunteer. The origin 

 of this remarkable occurrence was ascer- 

 tained, in the morning, to be the noise pro- 

 duced in the room above by the fall of a pair 

 of tongs. How long the dream had continued 

 in this instance is uncertain ; evidently not 

 for a period in the least comparable to that 

 required for the actual occurrence of the 

 events that had passed through the mind of 

 each ; and it is probable, from many similar 

 cases, that the lady was awoke by the noise 

 rather than by the fright. Thus a gentleman 

 dreamt that he had enlisted as a soldier, 

 joined his regiment, deserted, was apprehended, 

 carried back, tried, condemned to be shot, 

 and at last led out for execution. After all 

 the usual preparations, a gun was fired ; he 

 awoke with the report, and found that a noise 

 in an adjoining room had both produced the 

 dream and awoke him. The same feeling of 

 duration, arising out of the number of images 

 passing in succession through the mind, is 

 often experienced when we are well assured 

 that the whole duration of our sleep has not 

 exceeded a few moments. We have known a 

 clergyman fall asleep in his pulpit during the 

 singing of the psalm before sermon, and awake 

 with the conviction that he must have slept 

 for at least an hour, and that the congrega- 

 tion must have been waiting for him ; but on 

 referring to his psalm-book, he has been con- 

 soled by finding that his slumber has lasted 

 no longer than during the singing of a single 

 line. There would not seem, in fact, to be 

 any limit to the amount of thought which 

 may thus pass through the mind of the 

 dreamer, in an interval so brief as to be 

 scarcely capable of measurement ; and this 

 view is confirmed by the circumstance, now 

 well attested, that it is a common occurrence 

 in drowning for the whole previous life of the 

 individual to be presented instantaneously to 

 his view ; with its every important incident 

 vividly impressed on his consciousness, just as 

 if all were combined in a picture, every part of 

 which could be taken in at a glance. This, 

 again, is connected with the fact that the 

 operation of the associative principle may re- 

 produce in dreams the remembrance of facts 

 long since forgotten in the waking state. Such, 

 however, is by no means peculiar to the state 

 of dreaming; for in the waking state we often 

 retrace involuntarily and unexpectedly some- 

 thing which we have in vain attempted to 

 recall at will, and which might be said to 

 have passed from our mental grasp. 



From the foregoing and other similar facts 

 it has been argued, that all our dreams really 

 take place in the act of falling asleep or of 

 awaking ; so that even when we fancy that 

 we have been dreaming all night, our uncon- 

 sciousness has been really complete, except 

 at these momentary intervals. That this 

 doctrine cannot be altogether true is obvious 

 from the fact, that we can frequently detect 

 the character of a dream, and even in some 

 degree trace its progress, by the expression of 

 the sleeper's countenance ; so that dreams 

 certainly may occupy time, and occur during 



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